From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jon Masters Subject: Re: [PATCH] reduce export symbol CRC table size on 64-bit archs Date: Fri, 10 Jul 2009 11:50:01 -0400 Message-ID: <1247241001.5006.11.camel@localhost.localdomain> References: <4A4A18780200007800008345@vpn.id2.novell.com> <4A4E671C.2090201@suse.cz> <4A51C71B0200007800008EE2@vpn.id2.novell.com> <200907092044.22108.rusty@rustcorp.com.au> <4A57089B0200007800009C0E@vpn.id2.novell.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4A57089B0200007800009C0E-Qfbpwmsw6RoS3W1tAdPHOtBPR1lH4CV8@public.gmane.org> Sender: linux-modules-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Jan Beulich Cc: Rusty Russell , Michal Marek , Ingo Molnar , tony.luck-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, Thomas Gleixner , linux-arch-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-modules-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org List-Id: linux-arch.vger.kernel.org On Fri, 2009-07-10 at 08:23 +0100, Jan Beulich wrote: > Actually I meanwhile think that module-init-tools can easily detect the changed > layout without any further kernel side adjustments: Since it is known that a > CRC always is a 32-bit value, simply checking whether the so-far-used 64-bit > value has more than 32 significant bits should suffice: If so, the new layout > is being used (with the symbol name starting at offset 4), else the old one is > in effect (name at offset 8). This ought to be a pretty trivial change to that > code. Agreed. That can be done. I won't get chance to do that until Sunday though because I'm about to be on a plane back from Tokyo to Boston and I expect a day of living hell with jetlag/email craziness. Jon. -- To unsubscribe from this list: send the line "unsubscribe linux-modules" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dallas.jonmasters.org ([72.29.103.172]:50849 "EHLO dallas.jonmasters.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752007AbZGJPum (ORCPT ); Fri, 10 Jul 2009 11:50:42 -0400 Subject: Re: [PATCH] reduce export symbol CRC table size on 64-bit archs From: Jon Masters In-Reply-To: <4A57089B0200007800009C0E@vpn.id2.novell.com> References: <4A4A18780200007800008345@vpn.id2.novell.com> <4A4E671C.2090201@suse.cz> <4A51C71B0200007800008EE2@vpn.id2.novell.com> <200907092044.22108.rusty@rustcorp.com.au> <4A57089B0200007800009C0E@vpn.id2.novell.com> Content-Type: text/plain Date: Fri, 10 Jul 2009 11:50:01 -0400 Message-ID: <1247241001.5006.11.camel@localhost.localdomain> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-arch-owner@vger.kernel.org List-ID: To: Jan Beulich Cc: Rusty Russell , Michal Marek , Ingo Molnar , tony.luck@intel.com, Thomas Gleixner , linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, linux-modules@vger.kernel.org, hpa@zytor.com Message-ID: <20090710155001.32nLhMrdjQiUZsbJG445_-HXFgn3SD--nThq02v_4jE@z> On Fri, 2009-07-10 at 08:23 +0100, Jan Beulich wrote: > Actually I meanwhile think that module-init-tools can easily detect the changed > layout without any further kernel side adjustments: Since it is known that a > CRC always is a 32-bit value, simply checking whether the so-far-used 64-bit > value has more than 32 significant bits should suffice: If so, the new layout > is being used (with the symbol name starting at offset 4), else the old one is > in effect (name at offset 8). This ought to be a pretty trivial change to that > code. Agreed. That can be done. I won't get chance to do that until Sunday though because I'm about to be on a plane back from Tokyo to Boston and I expect a day of living hell with jetlag/email craziness. Jon.